Marguerite is lovely.
Mavis would work, but I'm not too fond of the sound of it. I prefer
Maeve.
Margo /
Margot and
May /
Mae "
Maisie" would work as well even though they were originally and still are nicknames for
Margaret.
Other ideas:
Maia - If you go with the MAY-a pronunciation, this will work.
MaireadMared